When I bought my thermal "scanner" I doubted how much I would really use it. I mean I knew what I wanted to use it for, but didn't think I'd get to. (and I was right) I did find that I used it a lot more than I thought I would, at least the last two years. (this year not so much).
I used to check fields in the morning and evenings, not looking for deer (hunting wise), but rather looking to not bump / spook them before I crossed the fields. When they were there I'd go the long way 'round instead.
I did spot a bedded doe out in the field one early rainy morning before sunrise, that never would have seen with my naked eye. I mean even well after sunrise I couldn't see her, but knew she was there. I just sat and watched hoping she had a boyfriend around.
I've used it to help search for deer in the woods in the dark (both times pretty sure they hadn't been hit, but wanting to be extra sure).
I used it to roost turkeys in the evening on the edge of a field. We knew where they'd been roosting, knew where they were earlier, but couldn't see them in the trees. But were able to see them with the thermal. Interestingly though I couldn't see them the next morning and assumed they'd moved later or had flown down early.(They were 350 ish yard away, mostly roosted a little way inside the woods.) Either they'd got cold enough or there was too much fog and morning dew for that distance, I dunno. But we learned the hard way they were still there when we scared them off. lol
I realized the other day when I saw it that I didn't use it at all this year, spring or fall. Its because I didn't get to hunt much at all, and can no longer hunt those fields even when I did. :(
Another thing I sort of hoped is that you'd be able to blood track with it, but learned it doesn't work. One because my unit's not made for looking up close at things, but more importably any blood cools so fast you'd have to start looking almost imeditely.